Buck Transformers 3

[banshee1]

One of our CNC machines required 220v (+/-10% according to manu.), but the 208v panel was at it's max. load so the electrician wired the machine to the 240v panel and put two buck transformers inline to drop the voltage. His reasoning was the 240v panel was a little over and the manu. was very adamant about the +/-10%.

My problem now is I have a burned out motor and when I checked the voltage of each leg to ground 2 legs show 235/240v and the 3rd leg shows 40/50v. When I check any 2 legs to each other I see 214v on the meter. This doesn't make sense to me from what I understand about electricity. Each leg should be 110v approx. when checked to ground and 220v when check to each other correct? I even see the same readings when I checked the output side of the machines main power switch.

Can anybody explain this? I don't understand/know why 2 legs show 230/240v while the 3rd is so low or how everything works powered like this. I know/understand very little about AC, DC I understand.

We've had the machine for 2 years now and everything works, and from what I can tell all of the secondary motors (coolant pumps, chip conveyors and such) are wired for 220v. The work lights could be wired for 110v, but it's not easy gaining access to them so I haven't verified but the are working just fine.

Thanks.

 

[waross]

You may be able to use the original rotor and shaft in the new stator.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[firstoption]

I think you have blinders on

it seems to me that you're being trolled on as well.

 

[iceworm]

... but the machine itself is rated at 220v 50/60Hz

... 3phase, 4P, 220v, .26A, 1600rpm, 25W

.

... S5T6 probably indicates a special integrated gear box

I'm out of my element. Requesting education.

I've never seen a motor rated for 50/60 Hz. But this one is 25W(?), and it has a gear box. 1600rpm doesn't match with anything, but it has a gear box. 4P, 50Hz >> 1500rpm, geared up. 4P, 60HZ >> 1800rpm geared downed.

The motors are three phase, how does it regulate speed? Not regulated - speed doesn't matter? Little VFDs? Something else of which I have no knowledge?

iceworm

Harmless flakes working together can unleash an avalanche of destruction

 

[waross]

A high slip motor. 1800 RPM with 200 rpm slip = 1600 RPM.
Possibly similar to a design D motor.
At 25 Watts the lower efficiency of a high slip motor will not be much of an issue.
At 1/30 HP, it doesn't take much over design to make the motor suitable for the V\Hz ratio at either 50 Hz or 60 Hz.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[banshee1]

I've never seen a motor rated for 50/60 Hz.

The machine itself is rated for 50/60Hz (motor itself has nothing about that on it).

The motors are three phase, how does it regulate speed? Not regulated - speed doesn't matter? Little VFDs? Something else of which I have no knowledge?

No speed regulation on motor. The gearbox is attached to a Ø10" plastic disk used to collect tramp oil off the top of the cutting coolant.

Once I verify the output shaft on the motor itself matches, I'm probably gonna pick up a 4IK25GN-SW2T and wire it up. Don't see any reason why it shouldn't work.

Thanks for the help guys.